Extraction of oleaginous materials from solid substances



Feb. 23, 1954 ADAMS 2,670,317

EXTRACTION OF OLEAGINOUS MATERIALS FROM SOLID SUBSTANCES Filed May 2'7, 1949 N ji'Y/l? (07": Gea'zsye 11742102;

peratures.

solvent under high pressure.

Patented Feb. 23, 1954 EXTRACTION OF OLEAGINOUS MATERIALS FROM SOLID SUBSTANCES George F. Adams, Riverside, Ill., assignor to Universal :Oil Products Company, Chicago, 111., a

corporation of Delaware Application May 27, 1949, Serial No. 95,753

4 Claims.

This invention relates to a novel method of It is more particularly concerned with a relative- 1y simple and economical method of extracting oil from tar sands and the like.

A number of methods have been proposed for the recovery of hydrocarbons from solids such as shale, torbanite, and tar sand. One method comprises extraction with a solvent in which the hydrocarbons are readily soluble. Propane and other liquefied normally gaseous parafiins are excellent solvents at somewhat elevated tem- In addition, they possess the further advantage of enabling a separation between the oil and asphaltic constituents thereof to be effected by merely heating the liquid extract. However, the large scale adoption of continuous extraction processes utilizing solvents of this type has been hindered by the problems associated with the charging and discharging of solids to a vessel containing a liquefied volatile The process that I have invented avoids this disadvantage of the prior art processes. My invention is based on the discovery that propane and similar substances will extract "oil and asphalt from-materials such as Athabaska tar sand near the atmospheric boiling point of the extractant.

In one embodiment my invention relates to a method of extracting oil from oleaginous solids which comprises contacting at substantially atmospheric pressure an oleaginous solid with a liquefied normally volatile solvent to dissolve the oil in said solvent, separating the solution of oil and solvent from the extracted solid, heating the solution under pressure to form at least two liquid phases, and recovering the solvent from said phases.

In a more specific embodiment my invention relates to the process of extracting bitumen-containing solid material which comprises dissolving at least a portion of the bitumen by contacting at substantially atmospheric pressure said solid material with a liquefied normally gaseous hydrocarbon, separating the solution from the extracted solid material, heating the solution to a temperature sufiicient to precipitate an asphalt phase, separating and heating the remaining solution to precipitate an oil phase, recovering the solvent, and returning at least a portion thereof to the extraction step. 7

In a still more specific embodiment my invention relates to a process which comprises continuously counter-currently contacting at substantially atmospheric pressure finely divided tar sand with propane to thereby extract oil and asphalt from said tar sand and form a solution of oil, asphalt, and propane, withdrawing said solution and heating the same under pressure to a temperature sufficient to form two liquid phases comprising a propane-oil phase and an asphalt phase, separating said phases and heating the propane-oil phase under pressure to form a propane phase and an oil phase, separating said phases, and cooling and returning at least a portion of said propane phase to the extraction step.

The solid material charged to my process may be either organic or inorganic, but it should contain an oil, wax, bitumen, etc., that is capable of being extracted by the volatile solvents employed. My process is most beneficial when materials such as oil or tar sands, shales, lignites, torbanites, and the like, that contain oils and bitumens, comprise the charging stock. These materials ordinarily are crushed or pulverized to a relatively finely divided state before they are charged to the extraction step in order that more efficient and rapid extraction may be effected. My process can also be used to advantage in some instances in the extraction of oils from organic material such as soybean or cottonseed meal.

The extracting agents used in my process may be any volatile solvents that are capable of removing oleaginous materials from solids. However, my process is best carried out with hydrocarbons, particularly parafiins, that are normally in the vapor state at atmospheric pressure and temperature. Such hydrocarbons include methane, ethane, propane, isobutane, normal butane, and mixtures thereof. Because of its desirable properties, including its high solvent power and its ability to efi'eot separation between the asphaltic and non-asphaltic hydrocarbons, propane usually is the extracting agent employed in my process.

Although my process may be conducted batchwise, the preferred method of operation is of the continuous type. My invention will now be further described in connection with one mode of continuous operation.

Referring to the drawing, finely divided Athabaska tar sand containing about 16% bitumen is passed through line I containing valve 2 into the top of extraction tower 3. Liquid propane enters tower 3 near the bottom through line d. The pressure in the tower is atmospheric and the temperature is maintained at approximately -44 F., the atmospheric boiling point of propane. As the tar sand descends through tower 3 it is scrubbed by the upflowing stream of propane and the oil and asphaltic material in the tar sand dissolves in the propane. In order to effect better contact, mechanical agitation may be resorted to. The ratio of solvent to solid material that .is employed is dependent upon the lnaturerdfithe materials, including the amount of bitumen in the sand, and the degree of extraction desired. In this particular illustration, 0.5 gallon of propane per pound of tar sand will substantially completely remove an of the oil and asphalt from the sand and "form a single hydrocarbon phase. If too .muchzpropane is used, asphalt sometimesprecipitates out of the propane in this zone.

The extracted sand is removed from column .3 through line 5 containing valves, 'and'may' beserlt to means for recovering the propane :from the sand. The propane may then be returned to the 1 ."system.

Propane containing dissolved .oil and asphalt lisiwith'drawnlirom column.3 an'd'is-passedthrough i'line 7!, pump i3, and "line 9 into column 1.0 .near l'themiddlethereof. Relatively cold 60-80 Fl) propane 'ispassedlinto column lilnear thelbot- "tom through line 1] containing valve 12. The material in the top .of column in .Lisheated to a temperature .o'f;abou't 1'5'0' R'by means ofsteam fcoils I 3. Asphalt is precipitated fromthesolution in this column. The asphalt phase, being .the heavier, starts for thebottom of the tower and, as it descends, it is scrubbed by the upcoming stream ofgpropanehand the more soluble .oil which mayfhave started down with the asphalt is dissolved in the ascending .propane. The asphalt, which contains a minor amount of propane, is 'withdrawn'from column .it through line M containing valvelS. iTh'e substantially asphalt-Tree, propane-nil phase is 'withdrawnffrom column it through'lin'e containing valve llanddspassed to column .I 8.

An alternative method of removing asphalt from the propane-:oil-asphalt phase withdrawn from column 3 comprises passing said phase 'through .a heater with or without additional propane and "thereatter passing theiheate'd solution "into a settler, which would take the place of column ID.

The material in column 18 is heated by means of steam coils '30 to :a temperature substantially equal to :or somewhat in excess of the "critical temperature zoifipropaneii. e.,.206F. This causes fthesdlution 'to separate iIItOutWO'ljhflSBS; one of \vhiehis a substantially .pure ipropane phase and the'o'therof whichis'a gas oilphase containing some propane. The propane'phase is withdrawn from-column 18 through line i'B'containing valve 20 'andis'cooled by means not shownon'th'e drawin'g'and is re'tumed to column 3 v'ialine Confsiderable economy can be effected by heatexchanging the propane flowing through line [9 with the feed to columns Ill and 18, i. e., the material flowing throughlines -9 and 16. Additional propane may be added to or withdrawn from the system as required through line 2| containing valve 22. The gas oil phase is withdrawn from column I8 through line 23 containing valve 24 and is sent to propane recovery means.

:As pointed ou-t in connection uwithrcolumn I ll, column .1 8 .mayfbe used zasza settler iii .the material charged thereto has been heated to a temperature sufficient to form two phases. Another means of separating the oil and propane withdrawnas a solution from column 10 comprises "vaporizing the propane. However, this method .requires:a great .deal more heating and cooling than :does the=method described.

17min athezforegoing it can be seen that I have inventeda method of removing oleaginous mate- 'rialsfrom'soli'ds"containing the same, said method being characterized by the use of liquefied normally gaseous solvents at substantially atmospheric pressure. The charging and discharging .nf solid -material 'to high pressure equipment .is avoided and excellent extractions .an'd .separa- .tions can ".be easily and economically e'irecte'd. My process is particularly advantageous when .usedto extract 011 and asphalt .frompetroleumbearing solids .such asi-tar sands.

I claim as my invention:

1. A process for extracting oil and asphalt Jfrom a solid materialcon'taining'thesame, which comprises contacting the .solid material with a liquefied normally gaseous ihyldrocarbon solvent .at -.approximately atmospheric pressure .and .at .ahou'tthe. .atmosphericlbo'ilingpoint-of .thesolverit to dissolve .oil and asphaltin-the-solvent, separating the resultant solution-rromthesolid-material, heating.said.solution:under-pressureto,precipitate asphalt therefromand-recoveringthe precipitated asphalt, .further .heating the remaining .solution -.o.f oilancl solvent i under v.prt-z-ssure $0.61, .least the critical temperature of .said solvent .to .form a diquid .oil .phase and a liquid solvent .phase, and separating said phases .from each other.

2. The process of claim 1 .further characterized .in .that'at least.a portion of theseparated solvent phase :is returned to .the extraction step.

.3. .Theprocess otc'laiml further characterized in that said solventcomprises;propane.

A. .The .process .of claim .1 .iurther .character- .izeddnthatsaid solid materialis a .tar.sand.

.GEORGE E. .ADAMS.

References Cite'diin zthe .fi1e-df this patent STATES PATENTS Number Name Date 11607977 Armstrong Nov. '23, I526 2,115,003 iBe'iswenger Apr. "26, 1938 2,132,441 Rosenthal Oct. ll, 15933 21885012 Pilatet 'al ..-"Jan. 23, 1940 "2202589 Lewis =et al. May 28, 1940 2252,86 1 schaaisma Aug. '19, 19491 2,284,583 Lewis May26, I942 2,1'56-7;'6l-1 Dickinsomet a1. -'Jan. 28, I915 

1. A PROCESS OF EXTRACTING OIL AND ASPHALT FROM A SOLID MATERIAL CONTAINING THE SAME, WHICH COMPRISING CONTACTING THE SOLID MATERIAL WITH A LIQUEFIED NORMALLY GASEOUS HYDROCARBON SOLVENT AT APPROXIMATELY ATMOSPHERIC PRESSURE AND AT ABOUT THE ATMOSPHERIC BOILING POINT OF THE SOLVENT TO DISSOLVE OIL AND ASPHALT IN THE SOLVENT, SEPARATING THE RESULTANT SOLUTION FROM THE SOLID MATERIAL, HEATING SAID SOLUTION UNDER PRESSURE TO PRECIPITATE ASPHALT THEREFROM AND RECOVERING THE PRECIPITATED ASPHALT, FURTHER HEATING THE REMAINING SOLUTION OF SOIL AND SOLVENT UNDER PRESSURE TO AT LEAST THE CRITICAL TEMPERATURE OF SAID SOLVENT TO FORM A 